1. Field of the Invention
One disclosed aspect of the embodiments relates to a photoelectric conversion apparatus and an image pickup system, and in particular, to a photoelectric conversion apparatus and an image pickup system in which the pixels each have an analog-to-digital conversion unit.
2. Description of the Related Art
An image sensor having a configuration in which each pixel includes means for analog-to-digital conversion (hereinafter referred to as AD conversion) is disclosed in Japanese Patent Laid-Open No. 2006-203736. With this configuration, an operation from exposure of the sensor to AD conversion of a signal can be performed together by all the pixels.
However, assuming that the resolution of AD conversion is N-bit (N is a natural number), N signals need to be always read out from the individual pixels, and thus, the frame rate is controlled. This makes it difficult to increase the frame rate.
One disclosed aspect of the embodiments solves the above problem.